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Real-Time Rendering of Planets with Atmospheres. Tobias Schafhitzel, Martin Falk, Thomas Ertl Universität Stuttgart, Germany. Motivation. Outline. Introduction Atmospheric scattering Computation of the scattering texture Rendering Results Conclusion and future work. Outline.
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Real-Time Rendering of Planets with Atmospheres Tobias Schafhitzel, Martin Falk, Thomas Ertl Universität Stuttgart, Germany
Motivation Tobias Schafhitzel – Real-Time Rendering of Planets with Atmospheres
Outline • Introduction • Atmospheric scattering • Computation of the scattering texture • Rendering • Results • Conclusion and future work Tobias Schafhitzel – Real-Time Rendering of Planets with Atmospheres
Outline • Introduction • Atmospheric scattering • Computation of the scattering texture • Rendering • Results • Conclusion and future work Tobias Schafhitzel – Real-Time Rendering of Planets with Atmospheres
Introduction • Rendering a planet’s atmosphere • Physically based computation • color shifts, light attenuation • Sunset, sunrise, midday • Combination with terrain rendering • Real-time approach • Games • CAD • Explorative tools (i.e. Google Earth,…) Tobias Schafhitzel – Real-Time Rendering of Planets with Atmospheres
Previous Work • Atmospheric Scattering • Atmospheric Scattering Effects of the Earth [Nishita et al. 93] • Real-Time Atmospheric Scattering [O’Neil 04] • Interactive Rendering of atmospheric Scattering Effects using Graphics Hardware [Dobashi et al. 02] • Accurate Atmospheric Scattering [O’Neil 05] • Terrain Rendering • Real-Time continuous Level of Detail Rendering of Height Field [Lindstrom et al. 96] • Real-Time Generation of continuous Level of Detail for Height Fields [Röttger et al. 98] Tobias Schafhitzel – Real-Time Rendering of Planets with Atmospheres
Outline • Introduction • Atmospheric scattering • Computation of the scattering texture • Rendering • Results • Conclusion and future work Tobias Schafhitzel – Real-Time Rendering of Planets with Atmospheres
Atmospheric Scattering • Light scattering equation: Pv Pc Pa atmosphere φ Pb earth Tobias Schafhitzel – Real-Time Rendering of Planets with Atmospheres
Outline • Introduction • Atmospheric scattering • Computation of the scattering texture • Rendering • Results • Conclusion and future work Tobias Schafhitzel – Real-Time Rendering of Planets with Atmospheres
Computation of the scattering texture • Parametrization of the 3D scattering texture: • Arbitrary height h = |Pv| • For each h Arbitrary view angle θ • For each θ an arbitrary angle to the sun φ φ θ Pv h Tobias Schafhitzel – Real-Time Rendering of Planets with Atmospheres
PV PV PV Intersection Tests • Camera inside the atmosphere → use 1st intersection • Camera outside → no scattering → move camera to outer boundary → constant height for parameterization → use 2nd intersection • Two textures for intersections with • Inner sphere • Outer sphere • Easy to switch when rendering Tobias Schafhitzel – Real-Time Rendering of Planets with Atmospheres
Outline • Introduction • Atmospheric scattering • Computation of the scattering texture • Rendering • Results • Conclusion and future work Tobias Schafhitzel – Real-Time Rendering of Planets with Atmospheres
Rendering the sky • Sky: tessellated sphere • View ray Rv • connect vertex Pg with camera Pv • Compute h, θ and φand map to [0,1] • φis constant (directional light) • Fetch the scattering texture (simple lookup) Pc Pg φ Rv θ Pv Tobias Schafhitzel – Real-Time Rendering of Planets with Atmospheres
PV Rendering the terrain • More complex • Consider structure of the terrain • Naive computation fails • Distance too long • Terrain color not considered • Solution • Compute scattering along PvPb • Subtract contribution along PgPb • Two texture lookups: Pg Pb Tobias Schafhitzel – Real-Time Rendering of Planets with Atmospheres
PV Rendering the terrain II • Considering the terrain color • Illumination of the terrain • Incident light is attenuated: • Reflected light is attenuated • Overall light contribution: Pc Ig Igv Pg Tobias Schafhitzel – Real-Time Rendering of Planets with Atmospheres
Outline • Introduction • Atmospheric scattering • Computation of the scattering texture • Rendering • Results • Conclusion and future work Tobias Schafhitzel – Real-Time Rendering of Planets with Atmospheres
Results • Earth dataset (2572 x 24 x 12) • Mars dataset (652 x 24 x 12) All measurements in fps Tobias Schafhitzel – Real-Time Rendering of Planets with Atmospheres
Europe at morning Tobias Schafhitzel – Real-Time Rendering of Planets with Atmospheres
Alps at morning Tobias Schafhitzel – Real-Time Rendering of Planets with Atmospheres
Alps at midday Tobias Schafhitzel – Real-Time Rendering of Planets with Atmospheres
Sunrise Tobias Schafhitzel – Real-Time Rendering of Planets with Atmospheres